Plumbing Oil Lines From S&S 143 To Baker Oil Pan: The Ultimate Guide

Upgrading your Harley-Davidson with a massive S&S 143 cubic inch engine is a thrilling experience, offering raw power and an unmistakable rumble. However, that extra displacement generates significantly more heat and oil volume, making the transition to a high-capacity Baker oil pan not just an option, but a necessity for long-term reliability. Many riders struggle with the critical step of plumbing oil lines from S&S 143 to Baker oil pan, often facing confusion over fitting sizes, routing clearances, and pressure requirements. If you’ve ever worried about blowing a gasket or starving your engine of oil on a hot summer ride, you are in the right place. This guide will walk you through the exact process to ensure your build runs as cool as it looks.

Why Proper Oil Plumbing Matters for Big Inch Engines

When you jump from a stock 107 or 114 motor to an S&S 143, the dynamics of your lubrication system change dramatically. The larger displacement means more oil is circulating, and the increased friction surfaces generate higher operating temperatures. A standard stock oil pan simply cannot handle the thermal load or the oil capacity required to keep these big inches happy.

According to general automotive engineering principles, increasing engine displacement without upgrading the cooling and lubrication infrastructure can lead to premature wear. As noted in resources regarding internal combustion engines, proper oil viscosity and flow rate are critical for maintaining the hydrodynamic film between moving parts Wikipedia.

Key Risks of Improper Plumbing:

• Oil Starvation: Incorrect line diameter can restrict flow to the oil pump.
• Heat Soak: Inadequate oil volume leads to rapid temperature spikes.
• Vibration Fatigue: Rigid lines near a high-torque 143 motor can crack under stress.
• Clearance Issues: The S&S case dimensions differ slightly from stock, risking line rub against the frame or Baker pan fins.

By correctly plumbing oil lines from S&S 143 to Baker oil pan, you ensure that your investment lasts for tens of thousands of miles without catastrophic failure.

Essential Tools and Parts Checklist

Before you lift the motorcycle, gather the correct components. Guessing measurements on a custom build is a recipe for disaster. Here is what you need for a professional-grade installation.

Required Components

Pro Tip: Always measure twice. The distance between the S&S 143 feed/return ports and the Baker pan inlet/outlet varies depending on your specific frame geometry (Softail vs. Touring).

Step-by-Step: Plumbing Oil Lines From S&S 143 To Baker Oil Pan

This section details the physical installation. Follow these steps meticulously to avoid leaks and ensure optimal flow.

Step 1: Identify Feed and Return Ports

Confusing the feed and return lines is the most common mistake.

• S&S 143 Engine: Typically, the feed line (pressure to pump) is located on the lower front of the case, while the return line (oil from tank/pan) is on the rear or upper section. Consult your specific S&S manual, as casting changes occur.
• Baker Oil Pan: The port closest to the front of the bike is usually the suction/feed to the pump. The rear port is the return from the oil cooler or tank.

Action: Mark your lines immediately with red tape (Feed) and blue tape (Return) before cutting or bending anything.

Step 2: Dry Fit and Route the Lines

Do not tighten fittings yet. Thread the stainless braided lines through the frame.

1. Start at the Baker oil pan. Attach the swivel fittings loosely.
2. Route the line upward, avoiding sharp bends. A bend radius tighter than 1.5 times the hose diameter can restrict flow.
3. Bring the line to the S&S 143 case.
4. Ensure there is at least 1/4 inch clearance between the oil line and any frame tube, exhaust header, or the pan fins themselves. The S&S 143 vibrates differently than a stock motor; give it room to move.

Step 3: Measure and Cut (If Using Bulk Hose)

If you are assembling your own lines:

• Measure the length needed while the fittings are threaded onto the hose ends but not tightened against the flare.
• Add 0.5 inches of slack to account for engine movement under torque.
• Use a dedicated hose cutter or a very fine-tooth hacksaw. Do not use a grinding wheel, as it can melt the inner PTFE liner.
• Target Length Example: For a typical Softail frame with an S&S 143 and deep Baker pan, the feed line is often around 24–26 inches, and the return line is 28–30 inches. Verify this on your specific bike.

Step 4: Apply Sealant and Tighten

1. Clean all threads with brake cleaner.
2. Apply a thin layer of high-temperature thread sealant to the male NPT threads only. Never put sealant on the flare seat, as this causes leaks.
3. Hand-tighten the fittings into the S&S case and Baker pan.
4. Use two wrenches: one to hold the adapter stationary and one to turn the swivel nut. This prevents twisting the internal hose structure.
5. Torque to manufacturer specifications (typically 15–20 ft-lbs for AN fittings, but check your hose brand guidelines).

Step 5: Secure with Clamps

Vibration is the enemy of big-inch motors. Install cushioned P-clamps every 6 to 8 inches along the run.

• Ensure the clamp does not pinch the hose. It should be snug enough to prevent movement but loose enough to allow slight thermal expansion.
• Avoid mounting clamps directly to the engine cases; mount them to the frame or transmission housing.

Common Challenges and Solutions

Even experienced mechanics face hurdles when plumbing oil lines from S&S 143 to Baker oil pan. Here is how to overcome them.

Challenge 1: Exhaust Interference

The massive headers on a 143 build often cross right where the oil lines want to go.

• Solution: Use double-swivel fittings (90-degree on one end, 45-degree on the other) to “snake” the line behind the exhaust pipes. Never let the oil line touch the exhaust; the radiant heat can degrade the hose outer braid over time.

Challenge 2: Frame Clearance on Softails

Softail frames have tight triangulation near the backbone.

• Solution: You may need to route the lines internally through the frame loop if your frame allows, or use ultra-high-pressure rigid tubing for the final bend, connected by flexible hose sections. Note: Rigid tubing requires professional bending tools.

Challenge 3: Leaks After First Heat Cycle

It is normal for fittings to seep slightly after the first heat-up and cool-down cycle due to thermal expansion.

• Solution: Run the engine until operating temperature, let it cool completely, and then re-torque the fittings by a quarter turn if necessary. Check for drips.

Comparison: Stock Lines vs. Upgraded Braided Lines

FAQ Section

1. What size oil lines do I need for an S&S 143?

For an S&S 143 cubic inch engine, it is highly recommended to use -8 AN (1/2 inch) lines rather than the stock -6 AN size. The larger displacement requires higher oil volume flow to maintain pressure and cooling efficiency. Using -6 lines can create a bottleneck, leading to increased oil temperatures.

2. Can I reuse my old stock oil line fittings?

No. Stock fittings are typically designed for rubber hoses with crimped ends or specific JIC flare angles that do not match stainless braided AN fittings. Furthermore, the thread pitch on the S&S 143 case and Baker oil pan often differs from stock Harley-Milwaukee-Eight ports. Always use new, matched fittings provided by S&S or Baker.

3. How do I know if my oil lines are routed correctly?

Correct routing ensures no kinks, no contact with moving parts (belt drive), and no contact with hot exhaust pipes. A good test is to have a helper turn the handlebars lock-to-lock while you inspect the lines for tension. There should be enough slack so the lines never pull tight during steering or suspension compression.

4. Do I need an external oil cooler with this setup?

While the Baker oil pan adds capacity and surface area for cooling, an external oil cooler is strongly advised for S&S 143 engines, especially if you ride in stop-and-go traffic or hot climates. When plumbing, include the cooler in the return line path (after the pan, before the tank, or pan-to-cooler-to-pump depending on your specific dry sump configuration).

5. What type of oil should I use after plumbing?

After installing new lines, always perform an oil change. For a 143 big twin, use a high-quality synthetic motorcycle oil rated for 20W-50 (for most climates) that meets JASO MA2 standards. The break-in period for new lines involves checking for leaks after the first 50 miles.

Conclusion

Successfully plumbing oil lines from S&S 143 to Baker oil pan is the bridge between a garage queen and a reliable road warrior. By respecting the increased demands of your big-inch engine, using high-quality braided lines, and following precise routing techniques, you protect your investment from heat and vibration damage. Remember, the devil is in the details: proper clearance, correct fitting torque, and regular post-installation checks are what separate amateur jobs from professional builds.

Now that your oil system is bulletproof, it’s time to fire up that 143 and feel the torque! Did you find this guide helpful? Share this article with your riding crew or post your build photos on social media using #SS143Build and #BakerDrivetrain. Let’s keep the rubber side down and the oil flowing!